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Understanding the causes of faints and fits in animals

A generic term to describe an animal that has an episode of falling down or recumbency, which can either be brief or for a long period of time. The causes of collapsing ranges from things like an abnormal heart rhythm disorder (faint/syncope), seizures (fits), medical conditions such as low blood glucose or an imbalance in electrolytes.

It is important to be aware that the abnormal movements during seizures/fits can be similar to the abnormal movements associated with a heart rhythm disorder (syncope/faint) which causes a lack of blood to the brain. In seizures there tends to be manic paddling/swimming movements, jaw chomping and excessive salivation. With some heart rhythm disorders, symptoms can be anything from being motionless and flaccid (dead-like) to spasms/stiffening of the legs and arching back of the head and neck (which can mimic seizures). It is estimated in human medicine that 20% of people initially diagnosed with seizures are later found to have a heart rhythm disorder; this is likely to be similar in veterinary medicine. It is also preferable to rule out a heart problem, before contemplating a brain scan that might require an anaesthetic.

A good description from the person that has witnessed the event/s is immensely useful. It can be useful to check the colour of the inside of the lips and gums to see if they were a normal pink colour or changed to become white or blue. Keeping a note of the duration of the collapse, or if it was triggered by something like excitement, or at a certain time of day, is useful. Try to note if your pet reacts to touch or calling its name, this can help to decide if it was unconscious or not; but please note that the eyes can remain open and staring when unconscious. When possible, taking movies of the collapsing events is especially useful, particularly to a Specialist more familiar with the subtle differences between the different causes.

Following a description of the events, the next step is a physical examination by your vet to check for any clues that might explain the collapse and guide which diagnostic tests need to be performed. A neurological examination is needed to check for any brain, spinal or nerve conduction problems. Comprehensive blood tests are often indicated to screen for medical causes of collapse or seizure, such as liver disease, abnormally low blood glucose, imbalance in the electrolytes or loss of blood (anaemia). Repeated blood tests might be needed in some cases, as some changes might not show in a blood test for the first 24 hours.

A heart rhythm disorder would warrant further tests on the heart such as an electrocardiogram. An ultrasound scan of the heart (+/- chest x-rays) would be indicated to screen for structural heart conditions. If there is a swollen abdomen, that might be due to fluid or haemorrhage, this would also warrant an abdominal ultrasound scan.

In animals with an intermittent collapse, then there is likely to be something intermittent that causes the collapse. This might be a pause in the heart rhythm or an abnormally fast racing heart. However diagnosis of these intermittent problems requires an ECG at the time of the collapse. This can be achieved by your pet wearing a heart monitor (Holter) in the hope that the collapse happens when this is worn. If the collapsing is triggered by certain events such as excitement or greeting someone, then replicating this behaviour is useful. It is only by diagnosing whether or not a heart rhythm disorder was the cause of the collapse, that treatment can be decided on. For example if the heart has intermittent racing episodes, then medication might help to prevent that from happening. Or if the heart is temporarily stopping, then a pacemaker would be able to keep it beating and prevent collapse. If your pet does not collapse when wearing the Holter, then it is difficult to rule out an abnormal rhythm disorder. In which case the Holter may need to be worn for a number of days, or repeated when the collapsing becomes more frequent. Alternatively a small recording device can be inserted under the skin near the heart.

Why should I bring my pet to Willows?

Our cardiology service is led by a team of recognised, accredited Specialists and we aim to provide the best possible care and treatment for your pet in our state-of-the art hospital.